Figure 14

The principle of Multiplex Ligation dependent Probe Amplification (MLPA). a. Probe pairs at different locations along the region of interest are hybridised specifically head-to-tail to the target sequence and subsequently ligated. The ligated probes are amplified by quantitative PCR using fluorescent labelled primers complementary to the tag-sequences and separated by capillary electrophoresis on an automated fragment analyzer. b. peak heights represent the amount of amplified product of each separate probe pair. c. By dividing the peak heights of the patient sample and a normal control for each fragment, the ratio's of 0.5 shown in the graph mark the deletion of certain probes located along the genome, indicating the presence of a deletion of one allele.